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Humans have long kept track of who’s the best—in the world, on this course, in this pool, in this incredibly niche event. Those benchmarks largely reflect what men have accomplished in sports. Men’s achievements have become the de facto measuring stick and framework to organize and understand athletic performance and progression, and women are judged by this standard too. Women have never been given the space to test their potential and to set their own benchmarks without the weight of expectations that have been tainted by what men have accomplished or misconceptions about women’s bodies.
What could women achieve if they were given a blank slate and nothing to compare themselves to? What if women were given the freedom to launch an entirely different athletic trajectory than men?
In the early 1990s, physiology professors Brian Whipp and Susan Ward looked at the progression of men’s and women’s world records in running events ranging from the 200 meters through the marathon. They found that men lowered their times at a fairly predictable rate across all events. Yet the rate of improvement for women, particularly in the marathon, was much steeper. Based on the data, they predicted that the gap in times between women and men in the marathon would cease to exist by 1998.
It didn’t quite play out that way. In 1998, Ronaldo da Costa and Tegla Loroupe set new men’s and women’s marathon world records, but the gap between the record-breaking times was still more than fourteen minutes. And though the gap has edged slightly closer to twelve minutes between the current world records, there’s still a 9.7 percent difference today.
One reason for Whipp and Ward’s overconfidence was that they treated race results as purely a mathematical equation and assumed that velocity would increase at a consistent rate. They failed to account for women’s late entry to long-distance running; women weren’t allowed to compete in the marathon until the 1970s. It made sense that women’s performances improved by leaps and bounds, particularly in the first few decades of participation, before leveling off.
Whipp and Ward also ignored fundamental differences in anatomy and physiology between men and women that could influence athletic performance. Before puberty, girls and boys are more or less athletic equals. But once sex hormones, particularly testosterone, flood the bodies of adolescent boys, everything starts to grow—hearts, lungs, muscles, and limbs. Their bodies lean out, which translates to more strength, power, and speed. Men also typically score higher on measures of aerobic capacity—how much oxygen they’re able to take up and use during exercise. With bigger lungs, they can take in more oxygen. With bigger hearts and higher hemoglobin levels, they can pump a greater amount of oxygen-rich blood to their muscles. With bigger muscles, they can extract more oxygen from the blood.
While estrogen can influence factors related to training adaptation, performance, and strength, its influence is less potent. “There are always going to be these fundamental differences between males and fe‑ males where the best male, under the right conditions, will outdo the best female,” says Sandra Hunter, director of the Athletic and Human Performance Research Center at Marquette University. On average, across athletic disciplines, women’s records are 9 to 12 percent lower than men’s records, whether it’s sprinting, jumping, throwing, or distance events.
However, that’s not the end of the story. As distances increase, some of the anatomical and physiological advantages enjoyed by men begin to wash out. Particularly in ultra-distance events—those that exceed six hours or running events longer than 26.2 miles—outcomes are less dependent on physiology or cardiovascular capacity alone, says Nicholas Tiller, an exercise physiologist who studies how the body responds to extreme endurance exercise and an ultramarathon runner himself. As distances stretch out over 50, 100, or 200 miles, athletes must account for and manage many more variables. Weather, nutrition, gastrointestinal health, fatigue, pain, and psychology all start to carry more weight. “If you start suffering from gastrointestinal distress and you start feeling nauseated, it doesn’t matter what your VO2 max is. It doesn’t matter how strong you are. It doesn’t matter how quickly you can run if you can’t even stand because you can’t get the calories in,” Tiller told me.
And it seems like women may be better able to juggle the multiple factors that go hand in hand with long distances. In 2020, researchers examined more than five million results from nearly 15,500 ultrarunning events to determine the average pace and finishing time across all participants. They found that as distance increased, the gap between women and men narrowed. While women were, on average, 11.1 percent slower than men in the marathon, that percentage dropped to 3.7 percent for 50‑mile races and just 0.25 percent for 100-mile races. At distances over 195 miles, women were 0.6 percent faster than men. In other words, the average woman was faster than the average man in superlong races.
As I sifted through the studies and anecdotes, I wanted to know if this trend reflected a true sex difference or if it could be sampling bias. Are the impressive performances by women ultra-athletes just a result of the best of the best lining up on the start line, or are they representative of what the larger population of women is capable of? Currently, it seems like it might be a case of sampling bias. Women constitute a small segment of entrants to ultra-events (they make up only 23 percent of total ultramarathon participants). Those who choose to race long distances are likely well-trained athletes, skewing the average woman’s performance toward the top of the heap. On the men’s side, the larger number of competitors is more likely to represent a wider range of experience and abilities, contributing to the men’s lower overall average times. Still, at the 2021 Western States Endurance Run, the oldest and one of the most prestigious 100-mile trail races, brutal temperatures whittled the field down to its lowest finishing rate in more than ten years. Yet three women finished in the top ten overall—a first in race history—and fifteen of the top thirty finishers were women. These numbers are hard to ignore.
Frankly, despite the curiosity, asking if and when women will outperform men isn’t the most salient question. Evaluating women’s results against the men’s standings continues to suggest that women are less than men and only worthy of accolades if they live up to standards set by and for men. It’s like saying they performed “good for girls.”
Instead, women’s achievements should be acknowledged as excellent on their own. This is not to say that we need to lower the bar when it comes to women’s sports. Rather, we need to shift the narrative to focus on women wholly rather than forcing them to measure up to a male paradigm. We need to recognize and celebrate women’s unique abilities and lived experiences. Then the question becomes, What makes women well suited to run, bike, hike, and swim long distances? And why do they tend to excel when events get longer and longer?
From Up to Speed: The Groundbreaking Science of Women Athletes, by Christine Yu, to be published May 16, 2023, by Riverhead, an imprint of Penguin Publishing Group, a division of Penguin Random House LLC. Copyright © 2023 by Christine Yu.